Development of Powder coatings for fire pipeline Ordinary fire galvanized steel pipe and fittings, due to its own poor performance in corrosion resistance, anti scaling and antibacterial, combined with the characteristic of fire water long-term static resistance and sudden urgent need, therefore there are so many problems for practice use: at first, because the galvanized steel pipe anti-corrosion performance is poor, long-term water erosion, the inner surface of the pipe is easy to rust, rust layer falling off easily plugging nozzle; Secondly, after the pipe inner surface scaling, it is easy to make the inner diameter of the pipe or congestion, reduce water and air base and even cannot transport, affecting the actual use effect; Moreover, the key point is that if the above situation appear in the process of fire disaster relief, once delay relief, consequence will be unimaginable. The existence of the above defects makes the service life of galvanized steel pipe short, usually only for 7 to 8 years. In addition, in the process of hot dip galvanized zinc vapour is easy to make the operation workers zinc poisoning, high temperature hot dip galvanized zinc ash and zinc liquid splash also easy to burn the operator, and hot dip galvanized is also bad for the environment. In order to avoid the above situation, many fire pipeline manufacturers use coating plastic pipe instead of common galvanized steel pipe, such as outside the steel pipe surface coated with a layer of powder coatings. After plastic coated steel pipe inner surface is smooth, fluid resistance is small, traffic increase, and no scaling, not easy to breed microorganisms, can fully guarantee the flow and use effect, energy conservation and environmental protection; And coating plastic pipe is with excellent chemical corrosion resistance, water resistance and alcohol resistance corrosion, high protein, high expansion foam extinguishing agent, can solve the problem of corrosion for the fire pipeline by water, buried and acid, alkali and salt, and greatly improve the service life of the fire fighting pipeline, reaching more than 50 years. In addition, the model steel works powder coating on the coating production personnel and coating contains no health hazard organic solvents; And powder coating is done in the closed system, spray from the powder coating can be recycled, the utilization rate of coating is above 98%. Moreover, most foreign building fire water supply system using copper tube and stainless steel tube, because of the copper pipe and stainless steel tube high cost, less used in engineering practice in our country. At present, the domestic fire sprinkler system feed pipe generally use galvanized steel pipe or galvanized seamless steel pipe . But as a result of galvanized pipe in corrosion resistance, fouling prevention and antimicrobial properties is poor, some fire fighting pipe manufacturers began to produce plastic coated pipe. Compare the price of galvanized pipe and coating plastic pipe, galvanized pipe is about 5000 ~ 6000 yuan/ton; Black pipe price is about 3380 yuan/ton, plastic coating steel pipe powder coatings are 35000 ~ 40000 yuan/ton, the coated plastic pipe price is about 5130 ~ 5380 yuan/ton. Considering the cost, the galvanized steel pipe and coated plastic tube is similar, but because of the service life of coating plastic pipe is 6 to 7 times the galvanized steel pipe, galvanized pipe and cost price and the service life of the coated plastic tube can be seen much more cheaper than galvanized pipe coated plastic pipe. Added indicators of “The automatic sprinkler system part 20: coated steel pipe” (1) vacuum resistance: section specimens (500±50) mm in length, using the appropriate measures
Ordinary fire galvanized steel pipe and fittings, due to its own
poor performance in corrosionresistance, anti scaling and
antibacterial, combined with the characteristic of fire water
long-termstatic resistance and sudden urgent need, therefore there
are so many problems for practice use: atfirst, because the
galvanized steel pipe anti-corrosion performance is poor, long-term
watererosion, the inner surface of the pipe is easy to rust, rust
layer falling off easily plugging nozzle;Secondly, after the pipe
inner surface scaling, it is easy to make the inner diameter of the
pipe orcongestion, reduce water and air base and even cannot
transport, affecting the actual use effect;Moreover, the key point
is that if the above situation appear in the process of fire
disaster relief,once delay relief, consequence will be
unimaginable. The existence of the above defects makes theservice
life of galvanized steel pipe short, usually only for 7 to 8 years.
In addition, in the processof hot dip galvanized zinc vapour is
easy to make the operation workers zinc poisoning, hightemperature
hot dip galvanized zinc ash and zinc liquid splash also easy to
burn the operator, andhot dip galvanized is also bad for the
environment.In order to avoid the above situation, many fire
pipeline manufacturers use coating plastic pipeinstead of common
galvanized steel pipe, such as outside the steel pipe surface
coated with a layerof powder coatings.After plastic coated steel
pipe inner surface is smooth, fluid resistance is small, traffic
increase,and no scaling, not easy to breed microorganisms, can
fully guarantee the flow and use effect,energy conservation and
environmental protection;And coating plastic pipe is with excellent
chemical corrosion resistance, water resistance andalcohol
resistance corrosion, high protein, high expansion foam
extinguishing agent, can solve theproblem of corrosion for the fire
pipeline by water, buried and acid, alkali and salt, and
greatlyimprove the service life of the fire fighting pipeline,
reaching more than 50 years. In addition, themodel steel works
powder coating on the coating production personnel and coating
contains nohealth hazard organic solvents; And powder coating is
done in the closed system, spray from thepowder coating can be
recycled, the utilization rate of coating is above 98%. Moreover,
mostforeign building fire water supply system using copper tube and
stainless steel tube, because of thecopper pipe and stainless steel
tube high cost, less used in engineering practice in our country.At
present, the domestic fire sprinkler system feed pipe generally use
galvanized steel pipe orgalvanized seamless steel pipe. But as a
result of galvanized pipe in corrosion resistance,
foulingprevention and antimicrobial properties is poor, some fire
fighting pipe manufacturers began toproduce plastic coated
pipe.Compare the price of galvanized pipe and coating plastic pipe,
galvanized pipe is about 5000 ~6000 yuan/ton; Black pipe price is
about 3380 yuan/ton, plastic coating steel pipe powder coatingsare
35000 ~ 40000 yuan/ton, the coated plastic pipe price is about 5130
~ 5380 yuan/ton.Considering the cost, the galvanized steel pipe and
coated plastic tube is similar, but because ofthe service life of
coating plastic pipe is 6 to 7 times the galvanized steel pipe,
galvanized pipe andcost price and the service life of the coated
plastic tube can be seen much more cheaper thangalvanized pipe
coated plastic pipe.Added indicators of The automatic sprinkler
system part 20: coated steel pipe(1) vacuum resistance: section
specimens (50050) mm in length, using the appropriate measures
to block pipeline import and export, import increase gradually
from negative pressure to 660 mmHg, keep 1 min, check internal
coating should not fall off after test.(2) high temperature
resistant performance: section specimens (100 + 10) mm in length,
place thespecimen in the incubator, heating up to 300 + 5 , and
constant temperature for 1 h, then takeout the natural cooling to
room temperature. After the test, remove the specimen and check
theinternal coating (allowing look dark, dark phenomenon) shall be
no loss, uplift, cracking, strippingand damage.(3) the low
temperature performance: the section length of specimen size (100 +
10) mm, placethe specimen in the low temperature box, cooled to -
30 + 2 , and constant temperature for 1 h,then remove them placed
it under the environment of a temperature of (20 + 5) for (4 ~
7)h.After the test period, remove the specimen examination inside
coating should be no loss, damage,and then press the CJ/T120-2008
stipulation 7.4.2 adhesion test, coating adhesion level should be1
to 3.(4) pressure cycle: section specimens (50050) mm in length,
using the appropriate measures toblock pipeline import and export,
and connected to water supply system, water filling out of theair,
and then from 3000 MPa (0.4 + 0.1) to the MPa alternating hydraulic
pressure test, each testcycle is not greater than 2 s. After the
test check that the internal coating should be free of loss,damage,
and then press the CJ/T120-2008 stipulation 7.4.2 adhesion test,
coating adhesion levelshould be 1 to 3.(5) temperature cycle:
section specimens (50050) mm in length, put in the following order
ineach specimen temperature for 24
h.502;-102;502;-102;502;-102.
After the test, the specimen is placed in a temperature of (205)
for 24 h, check that theinternal coating should be free of loss,
damage, and then press the CJ/T120-2008 stipulation 7.4.2adhesion
test, the coating adhesion level should be 1 to 3.(6) water of
heat-resistant aging: section specimen size length is about 100 mm,
section on bothends of the bare place treatment should be
accordingly, place the section in the distilled water (70+ 2) for
30 d, remove the natural cooling to room temperature after test,
check the inside ofthe specimen coating should not fall off.Since
adding above six indicators in the standard of the automatic
sprinkler system part 20: coatedsteel pipe according to the fire
fighting pipeline actual usage, the fire coated plastic
pipeproduction enterprises set out to do a lot of testing work
screening of powder coating, but existingpowder coating on the
market at present can not satisfy the automatic sprinkler system
part 20:coated steel pipe" such stringent requirements in the
standard. As a result, many powder coatingsmanufacturers started to
develop new powder coating which can satisfy the automatic
sprinklersystem part 20: coated steel pipe.
